The present disclosure relates generally to immersion photolithography and, more particularly, to an immersion photolithography system using a sealed wafer bottom.
Immersion lithography is a relatively new advancement in photolithography, in which the exposure procedure is performed with a liquid filling the space between the surface of the wafer and the lens. Using immersion photolithography, higher numerical apertures can be built than when using lenses in air, resulting in improved resolution. Further, immersion provides enhanced depth-of-focus (DOF) for printing ever smaller features. It is understood that the present disclosure is not limited to immersion lithography, but immersion lithography provides an example of a semiconductor process that can benefit from the invention described in greater detail below.